Many genes up-regulated in blastemal-predominant tumours compared to triphasic tumours (Table 3) are known to be involved in early kidney development (stromagenic and induction/aggregation phase), including the HOX genes (HOXA 10, 11, HOXC 4, 5, 6, 9, HOXD 3, 9, 10, 11) [30], the sine oculis homeobox homologues (SIX1 [31], SIX2 [32]), CITED1 [11], and ITGA8 [33, 34] (Table 3). This evidence concerns the gene SIX2 and neoplasm.